|Year : 2019 | Volume
| Issue : 3 | Page : 192-197
The degree of crown discoloration induced by a bioceramic and other conventional endodontic sealers
Rawan M Alotaibi1, Sahar M Altuwaijri2, Doaa R.M. Ahmed3
1 Restorative and Prosthetic Dentistry Department, College of Dentistry, Dar Al Uloom University; Endodontics Department, College of Dentistry, Riyadh Elm University, Riyadh, Saudi Arabia
2 Endodontics Department, King Abdul-Aziz Medical City, Ministry of National Guard; Endodontics Department, College of Dentistry, King Saud bin Abdulaziz University for Health Sciences, Riyadh, Saudi Arabia
3 Restorative and Prosthetic Dentistry Department, College of Dentistry, Dar Al Uloom University, Riyadh, Saudi Arabia; Restorative Department, Faculty of Dentistry, Alexandria University, Alexandria, Egypt
|Date of Web Publication||16-Aug-2019|
Dr. Doaa R.M. Ahmed
Associate Professor of Restorative Dentistry, College of Dentistry, Alexandria University, Alexandria, Egypt
Source of Support: None, Conflict of Interest: None
Objective: The aim of this study was to compare the degree of crown discoloration induced by a novel bioceramic and conventional endodontic sealers.
Materials and Methods: Thirty extracted maxillary central incisors were selected and randomly divided into three groups (n = 10), according to the assigned sealer: G1 – TotalFill, G2 – Apexit Plus, and G3 – AH Plus. Baseline color of the labial surfaces was obtained using a spectrophotometer. Standardized root canal preparation and obturation were completed using ProTaper system and gutta-percha with sealer cement. Access openings were sealed using light-cured resin composite. Specimens were stored in saline and placed in an incubator at 37°C until testing. Crown color was reassessed after 1 week, 1 month, and 3 months. Color change from baseline was calculated using the following equation: ΔE* = ([ΔL*]2 + [Δa*]2 + [Δb*]2)½. Data were analyzed using ANOVA, t-test, and Tukey post hoc test (at P≤ 0.05).
Result: In the three groups tested, the highest mean value of color change was found after 3 months, whereas the lowest was at 1 week. Changes were significant in all groups (P < 0.001 in G1 and G2, P= 0.009 in G3). At all assessment times, no significant difference was found between the three groups of sealers tested (P = 0.593, P= 0.185, and P= 0.33 at 1 week, 1 month, and 3 months, respectively). Nevertheless, G1 showed the highest and G3 the lowest color changes at both 1 and 3 months.
Conclusion: It was concluded that all sealers tested result in a measurable and gradual tooth color change. While the bioceramic sealer resulted in a slightly higher color change compared to calcium hydroxide- and resin-based sealers, the difference was not considerable.
Keywords: AH Plus, apexit plus, color change, endodontic sealers, totalfill
|How to cite this article:|
Alotaibi RM, Altuwaijri SM, Ahmed DR. The degree of crown discoloration induced by a bioceramic and other conventional endodontic sealers. Saudi Endod J 2019;9:192-7
|How to cite this URL:|
Alotaibi RM, Altuwaijri SM, Ahmed DR. The degree of crown discoloration induced by a bioceramic and other conventional endodontic sealers. Saudi Endod J [serial online] 2019 [cited 2020 Feb 18];9:192-7. Available from: http://www.saudiendodj.com/text.asp?2019/9/3/192/264646
| Introduction|| |
The esthetic appearance of teeth has recently become of prime importance for patients and dentists alike; however, tooth discoloration resulting from endodontic treatment remains to be challenging.,,
Endodontic sealers are used to seal off the root canal system, eradicate any remaining bacteria, and fill of irregularities in the prepared canal. Nevertheless, it has been shown that it may darken the tooth structure by time by penetrating into the dentinal tubules resulting in changes of the optical and chromatic properties of the dentin.,,,
The staining tendency of the sealers is imparted by their different formulations, which include constituents to improve their antimicrobial action, radiopacity, flow, and consistency. These constituents may remain unreacted or corrode due to the presence of moisture and/or by their chemical interaction with dentin.,
According to their main chemical composition, root canal sealers have been classified into zinc oxide–eugenol (ZOE)-, calcium hydroxide-, glass ionomer-, silicone-, resin-, and bioceramic-based sealers. Bioceramic materials have been introduced to endodontics primarily as root-end filing materials., Recently, their use has expanded to include coating metal implants,, restorative dental cement, and endodontic sealers. Their use as sealers was mainly due to their antibacterial effect, biocompatibility, minimal shrinkage or resorption, excellent sealing ability, improved root-dentin bonding, and quick set., The bioceramic sealers have been further classified according to their major constituent as: mineral trioxide aggregate (MTA)-based sealers, calcium silicate-based sealers, and calcium phosphate-based sealers.
The degree of crown discoloration resulting from the different types of endodontic sealers has been previously investigated. Several reports indicated that both ZOE-based and resin-based sealers result in greater crown discoloration compared to other sealer formulations., The greater discoloration induced by some resin-based sealers, in particular, AH26 (Dentsply, Germany) was attributed to the presence of the bismuth trioxide radiopacifier, which converts to green bismuth compounds and progressively turns into a black color., This has been latter overcome by newer formulation of this resin-based (AH Plus, Dentsply, Germany) marketed as an epoxy-amine resin-based sealer. Parsons et al. have compared coronal discoloration induced by four different endodontic sealers and found that calcium hydroxide-based sealer (Sealapex, SybronEndo, Orange, CA) resulted in lower discoloration compared to AH26 and Kerr Pulp Canal Sealer sealers.
Tooth discoloration induced by bioceramic materials used as dentin replacement material has been previously investigated. One of the most studied bioceramic materials is MTA which was reported to have excellent sealing properties and biocompatibility, but when first developed, had a gray color, which had greater capacity of discoloration due to the presence metal oxide in their component. It was later replaced by white MTA to overcome the discoloration. Nevertheless, according to Jang et al., discoloration resulting from the use of white MTA was still considerable.
Biodentine is a tricalcium silicate-based bioceramic material, introduced to the market in 2009 by Septodont (Saint-Maur-des-Fosses, France). Biodentine was claimed to overcome the drawbacks of MTA, such as handling property, setting time, and capacity of producing tooth discoloration. When used in vital pulp therapy, Biodentine showed a favorable effect on dentin bridge formation by promoting pulp healing and remineralization. Another category of bioceramic is calcium phosphate-based cement, first introduced as a restorative dental cement, by then more recently successfully used in endodontic treatment such as in pulp capping, apical barriers formation, periapical defect, periapical defect repairs and bifurcation perforation repair, and as endodontic sealers.
Of the few studies that evaluated crown discoloration induced by bioceramic sealers, Partovi et al. reported that apatite (a calcium phosphate-based sealer) causes low crown discoloration compared to other sealers (AH26, Endofill, and Kemdent ZnOE). Likewise, Ioannidis et al. compared crown discoloration induced by MTA Fillapex to Roth 811 (resin-based sealer) and found that Roth 811 induced fast and severe discoloration that exceeded the perceptibility threshold 1 week after sealer placement, whereas MTA Fillapex did not.
With the greater use of bioceramic sealers, their effect on crown discoloration remains uncertain and inconclusive in comparison to other commonly used sealers based on resin or calcium hydroxide. In view of the above, and with sparsity of data related to certain sealers' properties, the aim of the study was to compare the degree of crown discoloration induced by a novel bioceramic and conventional endodontic sealers.
| Materials and Methods|| |
The study methodology has been approved by the research and ethics committee of the College of Dentistry, Dar Al Uloom University, Riyadh, Saudi Arabia (#REC 0001). Extracted human maxillary central incisors were obtained from the Faculty of Dentistry, Cairo University, and placed in saline at room temperature. Thirty teeth were selected and evaluated to not having any cavity, dental filling, cracks, enamel defects, and/or pathologic discoloring. All thirty teeth were thoroughly cleaned with Ultrasonic Scaler, rubber cup, and pumice and then disinfected by immersion in 0.5% chloramine-T solution for 1 week before storage in normal saline at room temperature. All teeth were used within 3 months of extraction.
I – Grouping
The teeth were randomly divided into three groups of 10 teeth each (n = 10), according to the type of sealer tested. Types of sealer used, manufacture, and composition are showed in [Table 1].
|Table 1: Types, composition, and manufacturers of sealers used in the study|
Click here to view
II – Base color assessment
Pretreatment color readings of the entire labial surface of all teeth were obtained and recorded as baseline data to which all the posttreatment data were compared. Color assessment was done using Vita EasyShade Advance Spectrophotometer (Vita Zahnfabrik, Germany). Each specimen was measured three times, and the average of the measurements was recorded. To prevent optical changes caused by dehydration, the excess water was gently removed by air-drying for 1 s before color measurement.
III – Access opening and root canal treatment preparation
A single operator performed all the preparation, obturation, and restorative procedures. Access cavity was prepared in the testing groups using an Endo Access Bur (Dentsply Maillefer, Tulsa, Okla) with high-speed handpiece. A safe-ended bur (Dentsply Maillefer, Tulsa, Okla) was then used to complete the deroofing of the pulp chamber. A Barbed Broach Size 10 (Dentsply Maillefer, Tulsa, Okla) was used to remove the pulp. The coronal two-third of the canal was prepared using number 2 and 3 Gates Glidden Drills (Dentsply Maillefer, Tulsa, Okla). A No. 10 K-file (Dentsply Maillefer, Tulsa, Okla) was introduced into the canal and pushed into the apical part until the tip of the instrument was visible at the apical foramen. This length of the file was recorded and then after subtracting 1 mm from the recorded length, working length of the root canal was determined.
Canal preparation was completed to the working length by the use of ProTaper Rotary file (Dentsply Maillefer, Ballaigues, Switzerland) using a step-down technique, according to the manufactures' instruction. Thorough irrigation using 2.5% sodium hypochlorite followed by 17% ethylenediaminetetraacetic acid (SmearClear, SybronEndo, CA) was done throughout the procedure in order to remove the smear layer. According to the standard irrigation protocols, each solution was used for 1 min after changing the files. The canals were then dried with paper points (Dentsply Maillefer, Tulsa, Okla) followed by the obturation using single-cone technique with standardized GP cones (Dentsply Maillefer, Tulsa, Okla) and the tested sealer using a Lentulo spiral (Dentsply Caulk, Milford, DE, USA) that would reach the prepared working length and not bind to the prepared canal walls. The Lentulo spiral was rotated at low speed (300 rpm) for 20 s, always keeping the instrument 2 mm from the apex. The excess sealer in the coronal third of the teeth was removed with a small cotton pellet. The access openings were then sealed with light-cured resin composite filling material Filtek Z250 “shade A2” (3M ESPE, St Paul, MN).
Specimens were stored in normal saline and placed in an incubator at 37°C temperature of until testing.
IV – Posttreatment color measurement
To evaluate the crown discoloration subsequent of root canal treatment (RCT) with different endodontic sealer, crown color was assessed using a VITA Easyshade Advance after 1 week, 1 month, and 3 months. The data collected and color difference from baseline were calculated using the following equation:
ΔE* = ([ΔL*]2 + [Δa*]2 + [Δb*]2)½
where L* corresponds to the degree of lightness, a* to the green–red color component (−a* = green, + a* = red), and b* to the blue–yellow color component (−b* = blue, +b* = yellow).
The mean and standard deviation (SD) values were calculated for each group in each test. Data were explored for normality using Kolmogorov–Smirnov and Shapiro–Wilk tests. Data showed parametric (normal) distribution.
Repeated measure ANOVA was used to compare between more than two groups in related samples. Pair-wise sample t-test was used to compare between two groups in related samples. One-way ANOVA followed by Tukey post hoc test was used to compare between more than two groups in nonrelated samples.
The significance level was set at P ≤ 0.05. Statistical analysis was performed with IBM® SPSS® Statistics Version 20 for Windows (SPSS IBM, Armonk, NY, USA).
| Results|| |
Means of chromatic values (L*, a *, and b*) as well as mean and SD of coronal color change (ΔE) at each assessment time for the different groups tested are shown in [Table 2].
|Table 2: Mean of chromatic values and mean and standard deviation (SD) of coronal color change (ΔE) at each assessment time for the different groups tested|
Click here to view
For all three groups tested, ΔE was significantly different between the three assessment times (P < 0.001 for G1 and G2, and P = 0.009 for G3). Values assessed at 3 months were significantly higher than those assessed at 1 month and at 1 week.
No significant difference was found between the three groups of sealers tested at each assessment time (P = 0.593, P = 0.185, and P = 0.33 for 1 week, 1 month, and 3 months, respectively). Nevertheless, at both 1 and 3 months, the calcium silicate-based sealer group (G1) showed the highest (ΔE) (6.75 ± 1.5, 8.14 ± 1.90, respectively), while the resin-based sealer group (G3) showed the lowest (5.64 ± 1.26, 7.02 ± 1.64, respectively).
| Discussion|| |
The esthetic appearance of teeth plays an extremely important role in patient satisfaction. Nevertheless, it has been reported that all endodontic sealers used during root canal obturation cause a variable degree of coronal discoloration, hence come the importance of sealer selection in endodontic treatment.
The current study was conducted to evaluate the overall coronal discoloration resulting from a novel endodontic sealer TotalFill (calcium silicate-based sealer), in comparison to more conventional ones Apexit Plus (calcium hydroxide-based sealer) and AH Plus (Resin-based sealer). The use AH Plus has been previously reported to cause discoloration; no sufficient data are available on Apexit Plus as well as TotalFill.
Central incisors were used for this study because of their reasonably wide pulp chamber that facilitates placement of root canal sealer. All specimens were stored in relative humidity after extraction to avoid possible dehydration of dental tissue that could lead to change in the optical properties of teeth. After specimen preparation and obturation with the designated sealers, crown color changes were assessed over a period of 3 months. According to Akhavan et al., there is no general agreement regarding the time of tooth discoloration followed endodontic treatment and thus 3-month period was thought reasonable for this study, especially that it was demonstrated by Parson et al. that tooth discoloration happens mostly within the first 3 months of RCT.
Crown color was assessed using a spectrophotometer (VITA Easyshade Advance) at baseline and then at the different time intervals. Spectrophotometer measurement is considered as an accurate and reliable method for color determination and a good alternative to the more subjective (visual) method of assessment. The results indicated that all tested sealers caused significant progressive discoloration during the 3-month study period. The average color change for the three groups was ΔE = 3.11, 6.07, and 7.40 at 1 week, 1 month, and 3 months, respectively. According to Paravina et al., color change values >1.2 would be considered perceptible, and values >2.7 would be clinically unacceptable according to 50:50 published threshold. Johnston and Kao also reported that color change values ranging from 5.5 to 6.8 are considered unacceptable and requiring further treatment. This emphasizes the magnitude of the color change that was recorded with the sealers tested in the current study, which could be perceptible as early as 1 week after treatment and clinically unacceptable after just 1 month.,
The significant color change that progressively increased overtime with all sealers tested may be attributed to the canals' preparation method. Following recent clinical recommendations, the canals and access openings were washed out by EDTA (RC-prep) and sodium hypochlorite 5.25%, which result in smear layer removal, possibly allowing for sealer penetration in the exposed dentinal tubules. Penetration of the sealer into the dentinal tubules following smear layer removal has been documented by Sonu et al. who also demonstrated that sealer penetration is dependent of the sealer type, with the resin-based sealer AH Plus showing deeper penetration that the MTA-based sealer, MTA Fillapex. El Sayed and Etamadi attributed the increase color change over time to the longer exposure of the dentinal tubules to the sealer allowing for greater likelihood of sealer penetration, hence, the progressive increase in color change. From another perspective, the progressive increase in color change may also be attributed to changes in the sealers' chemistry that may occur by time as demonstrated by Davis et al. even without removal of the smear layer.
No difference in color change was found between the three groups of sealers tested at each assessment time. Nevertheless, the bioceramic-based sealer group showed the highest color change, while resin-based group showed the lowest color change at both 1 and 3 months. Several other studies have discussed color changes resulting from AH Plus, yet there is no general agreement regarding the relative degree of color change resulting from its use. As in the current study, Meinckes et al. and Lenherr et al. also reported least color change values with the use of AH Plus and speculated that this may be due to the presence of stable radiopacifier in its composition, which allows for color stability. Similarly, Akhavan et al. reported minimal coronal discoloration induced by AH Plus and comparable to MTA sealer. However, their reported ΔE value after 1 month was <3.3, value much lower than those obtained in the current study (5.64 ± 1.26). This discrepancy may have resulted due to differences in the specimens' preparation and measurement methods. The values obtained in the current study were, however, comparable to those reported by Elkhazin et al. who found that mean color change associated with the use of AH Plus at 2 weeks was 5.68, depicting a change visible to the naked eye.
Color changes found in this study with the use of a calcium hydroxide-based sealer (Apexit Plus) were 2.38 ± 1.24, 5.83 ± 1.43, and 7.32 ± 1.59 after 1 week, 1 month, and 3 months, respectively. These values ranged between the values obtained for the resin-based and the bioceramic-based sealers but with no significant difference. The color change may be attributed to the presence of bismuth hydroxide and bismuth carbonate in its composition. The bismuth ions may be responsible for the induced discoloration. A similar observation was reported by Lenherr et al. who found that ApexCal, also containing bismuth carbonate, resulted in a significant tooth color change. Pure calcium hydroxide based-sealers on the other hand did not show any significant color change over a 12-month study period, which further highlights the possible role of bismuth in the resulting discoloration.
Limited studies reported the tooth color changes of using bioceramic-based sealers and to the best of our knowledge, no studies reported the discoloration resulting from Totalfill sealer. In this present study, the TotalFill sealer group produced the highest color change compared to both AH Plus and Apexit Plus but with no significant difference. Contrasting results were reported by Partovi et al. They found that the bioceramic sealer produced the least amount of tooth discoloration compared to other sealers due to its composition (alpha-tricalcium phosphate and hydroxy-Sankin apatite and 5% iodoform), lack of eugenol, and its liquid is formed of water and polyacrylic acid.
It was interesting to note in the current study that the b* chromatic parameter is the parameter that has undergone the greatest change over time and subsequently mostly responsible for the overall color change recorded in all groups tested. The increase in the b* values recorded designates a yellower color change. Changes in the L* and a* values were negligible throughout the study time and in all tested groups, indicating minimal change in the lightness or degree of red/green chroma of the specimens. The composition of the bioceramic sealer containing di-and tricalcium silicates and that of the calcium hydroxide-based sealer may have been responsible for the increase in mineral content and the resulting change in the chromatic values. Nevertheless, it would be reasonable to suggest that sealer specific composition is more influential on the ultimate color change rather than sealer type.
Within the limitations of the current study, it can be concluded that sealers used in endodontic treatment could have a marked tooth staining potential that increases over time. The induced tooth color change is dependent on the chemical composition of the sealer rather than its type. Esthetic considerations should be taken into account when selecting the type of sealer to be used.
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Conflicts of interest
There are no conflicts of interest.
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[Table 1], [Table 2]